To reduce the control error in a quadrature closed-loop circuit of micro electro mechanical system (MEMS) disk resonant gyroscope, a full-closed loop control method of MEMS disk resonant gyroscope based on the stiffness axis declination angle prediction mechanism is proposed. The parameters of the quadrature closed-loop circuit are automatically optimized and adjusted by predicting the stiffness axis declination angle of MEMS disk resonant gyroscope. In addition, a digital full-closed loop control method based on the stiffness axis declination angle prediction mechanism is proposed to realize the digital full-closed loop control of the driving, detection, quadrature suppression, and mode matching. This method can improve the signal-to-noise ratio of quadrature suppression circuit, and enhance the gyroscope capability in the field of quadrature drift, zero output and bias instability suppression. Experimental results show that, after adopting the full-closed loop control method based on the stiffness axis declination angle prediction mechanism, the zero output of the MEMS disk resonant gyroscope is decreased from 0. 201°/ s to 0. 021 3°/ s and the bias instability is decreased from 39. 42°/ h to 1. 237°/ h, by 9. 44 times and 31. 86 times, respectively, which evaluate the effectiveness of this method for improving the performance of the MEMS disk resonant gyroscope.